R-(+)-2-(4-hydroxyphenoxy) propionic acid reacted with 3, 4-difluorobenzonitrile at 80°C in DMF gave (R) -2-[4-(4- cyano-2-fluorophenoxy) phenoxy] propionate potassium, which was esterified with butyl bromide to afford Cyhalofop butyl. The phase transfer catalyst tetrabutylammonium bisulfate catalyzed the reaction efficiently; the total yield was obtained 94.2% with 96% chemical and 98% e.e optical purity respectively